There are a number of physical failure mechanisms that can affect the reliability of a semiconductor device. Time dependent dielectric breakdown (TDDB) is one reliability test typically performed. TDDB tests the wear out of an insulating material leading to a conductive path through the insulating material. The TDDB lifetime depends on the quality of the insulating material. As technology progresses and thicknesses of insulating material decrease, maintaining TDDB lifetimes becomes more challenging and more critical.
Though TDDB produces useful data, it has disadvantages. One disadvantage is the time it takes to obtain test results. TDDB procedures are performed on packaged (assembled) devices. Thus, the test results are dependent upon packaging time, as well as the test performance time. Typical test performance times can run 6 to 7 days.
Thus, what is needed an efficient effective reliability assessment of semiconductor devices.